[WC-3162] DG: Add auto-select first row

[yordan-st]

Pull request type

New feature (non-breaking change which adds functionality)

---

Description

• We added a feature where developers can configure the first item of a DataGrid to be automatically selected when it first loads.
• This feature is intended for master-detail views, where the user wants the dataview not to be empty on first load.

What should be covered while testing?

• Configure 'auto select first row'
• Observe if the first item is selected
• Check if this selection persists when you move to another page of the DataGrid

[iobuhov]

This might block select all feature. Let's merge it first

[iobuhov]

1. Rebase to iobuhov_next
2. Add autoSelect prop to Datagrid.config
3. Add autoSelect prop to createSelectionHelper.ts from widget plugin grid
4. Add this code between lines 61-62 in createSelectionHelper

if (helper.type === "Single" && config.autoSelect) {
            const dispose = autorun(() => {
                const firstItem = gate.props.datasource.items?.[0];
                if (!firstItem) return;
                helper.reduceTo(firstItem);
                dispose();
            });
            add(dispose);
        }

[iobuhov]

You add more XML props than it should. Remove all extra props.
Also, remove changes you made selection/helpers.ts